I want to implement in-app billing for my application where users can purchase coins. However I want the users to get some free coins when they first try the game. How do I go about implementing this?
If I just store it in the app settings, they can just keep re-installing the game and getting the free coins again. And the SD card is not secure enough, I don't want people tampering with it easily.
I hope this isn't a duplicate but I looked around and couldn't find anything in the docs. Iv'e seen a few suggestions but they all include using your own server, which I do not want to do.